Bone derived fibers and oxygenated wound treatments

ABSTRACT

A composition for the treatment of wounds includes demineralized bone fibers (DBF) derived from allogeneic or xenogenic cortical bone and/or polymeric fibers made from resorbable and/or non-resorbable polymer, and the composition may also include an oxygen-generating material and/or an oxygen carrier.

This application is a continuation of U.S. Ser. No. 16/316,968 filed onJan. 10, 2019, which is a national entry of WO PCT/US2017/041574 filedon Jul. 11, 2017, which claims the benefit of U.S. 62/360,652 filed onJul. 11, 2016. These and all other referenced extrinsic materials areincorporated herein by reference in their entirety. Where a definitionor use of a term in a reference that is incorporated by reference isinconsistent or contrary to the definition of that term provided herein,the definition of that term provided herein is deemed to be controlling.

FIELD

The present invention generally relates to devices used in wound care,and in particular to the healing of wounds where vascularization iscompromised.

BACKGROUND

It has been estimated that about 26 million patients suffer from chronicwounds each year. Chronic wounds include diabetic foot ulcers, venousstasis ulcers, pressure ulcers, burns, and surgical wounds. Those athighest risk for developing chronic wounds include patients withdiabetes, disabilities, and the elderly. These patients suffer not onlyfrom the physical pain of the wound, but also from stress and a poorquality of life.

Standard treatment for chronic wounds usually involves cleaning thewound, debriding the wound, and applying a dressing to maintain a moisttissue environment conducive to healing. In many cases, treatment alsoincludes the use of antibiotics since chronic wounds are also frequentlyinfected. Antibiotics may be administered systemically and/or by using adressing containing an antibiotic.

Clinicians will also try to eliminate underlying factors that cause theformation of chronic wounds.

Unfortunately, a significant number of patients with chronic wounds arenot healed after 3 months, 6 months, or even after one year oftreatment. In the worst cases, amputation may be necessary, and elderlypatients may even develop sepsis and die.

There are a number of reasons why chronic wounds are difficult to heal.One reason is the lack of or delay in new blood vessel formation that isnecessary to provide oxygen to support newly deposited tissue during thewound healing process. A second reason is the lack of an adequatescaffold to support formation of a repair tissue.

Research on the formation of new Extracellular Matrix (ECM) in chronicwounds has led to the development, for example, of products likePromogran Prisma™ by Acelity (formerly Systagenix) which incorporatesoxidized regenerated cellulose (ORC). The ORC inhibits proteases inchronic wounds that are considered to be detrimental to the formation ofnew ECM in order to improve wound healing.

Clinicians have also experimented with the use of autologous woundhealing factors, derived from a patient's blood, to improve woundhealing. For example, the topical application of platelet-derived growthfactor (PDGF) has been investigated in the clinic. Studies have alsoevaluated the use of autologous platelet-rich plasma (PRP) in thehealing of chronic wounds. McNeil Pharmaceutical has also introduced arecombinant PDGF product, Regranex™ Gel, to heal diabetic ulcers.Unfortunately, in 2008 the manufacturer added a warning to the productnoting that an increased incidence of mortality secondary to malignancywas observed when patients were treated with three or more tubes of theRegranex™ Gel in a post-market retrospective cohort study.

Accordingly, there is a need for devices, such as implants anddressings, with increased oxygen content to stimulate the healing ofchronic as well as acute wounds.

SUMMARY

Some embodiments of the present invention include improved devices, suchas dressings and implants, for treating wounds. Some embodiments of thepresent invention include processes for making such devices.

Some embodiments of the present invention include improved methods fortreating wounds. For example the methods are disclosed for treatingchronic and/or acute wounds.

Embodiments of the present invention include devices, such as dressingsand implants, for the treatment of chronic or acute wounds that arederived from demineralized bone fibers. In some embodiments, the devicesinclude an oxygen carrier or a source of oxygen that is particularlyuseful when it is desirable to compensate for a lack of effective bloodflow in a region such as in a chronic wound. In some embodiments, theimplants are resorbable; provide a temporary scaffold for the in-growthof cells, tissues, and blood vessels to help regenerate theextracellular matrix; and deliver oxygen to the chronic wound. Thedressings and implants may also include antibiotics for the treatment orprevention of infection in the wound.

The devices allow delivery of oxygen to the wound in a controlled mannerfor a prolonged period of time. In some embodiments, the devices aremade from extra cellular matrix-derived materials. In some embodiments,devices made from ECM-derived materials may also include polymericcompositions, creams, and/or gels. The oxygenated cream or gel may beincorporated into the dressing or may be added at the time of initialdressing application. The oxygenated cream or gel may be applied atregular intervals, for example, daily, during the wound healing process.The extra cellular matrix derived materials may include fibers derivedfrom demineralized bone. Additionally, the demineralized bone may betreated to remove bone morphogenic proteins (BMPs). The bone may beallogenic or xenogenic. The xenogenic materials may be treated to reducetheir immunological potential. The polymeric compositions include butare not limited to, resorbable polymers.

According to some embodiments of the present invention, dressings mayhave a film laminated to the upper surface or a cover film dressing toact as a barrier to prevent oxygen and/or moisture loss from thetreatment into the atmosphere. In other embodiments of the presentinvention, dressings are used in conjunction with an adhesive filmdressing such as Opsite (Smith & Nephew) or Tegaderm™ (3M).

In some embodiments of the present invention, a composition for thetreatment of wounds, includes demineralized bone fibers (DBF) derivedfrom allogeneic or xenogenic cortical bone.

In some embodiments of the present invention, a composition for thetreatment of wounds includes polymeric fibers made from resorbableand/or non-resorbable polymer.

In some embodiments of the present invention, a composition for thetreatment of wounds includes DBF fibers and polymeric fibers made fromresorbable and/or non-resorbable polymers.

In some embodiments of the present invention, a composition for thetreatment of wounds includes DBF fibers and oxygen generating materialsand/or an oxygen carrier. In some embodiments, the oxygen generatingmaterials and/or the oxygen carrier is coated on the DBF or thepolymeric fibers. In some embodiments of the present invention, theoxygen generating materials are selected from the group consisting ofCalcium Peroxide, Magnesium Peroxide, Sodium Percarbonate, SodiumPeroxide, and mixtures thereof. In some embodiments, the oxygen carrieris a perfluorocarbon selected from perfluorodecalin, perfluorohexane,perfluoroperhydrophenanthrene, perfluorobutylamine (PFTBA or PFTBM),perfluorooctylbromide (PFOB), perfluoro-n-octane, octafluoropropane,perfluorodichlorooctane, perfluorodecalin (PFD),perfluorotripropylamine, perfluorotrimethylcyclohexane,perfluoromethyladamantane, perfluorodimethyladamantane,perfluoromethyldecaline, perfluorofluorene, diphenyldimethylsiloxane,hydrogen-rich monohydroperfluorooctane, alumina-treated perfluorooctane,or mixtures thereof.

In some embodiments of the present invention, a composition for thetreatment of wounds includes polymeric fibers made from resorbableand/or non-resorbable polymer, where the non-resorbable polymer isselected from poly(ethylene), poly(propylene),poly(tetrafluoroethylene), poly(methacrylates),poly(methylmethacrylate), ethylene-co-vinylacetate,poly(dimethylsiloxane), poly(ether-urethanes), poly(ethyleneterephthalate), nylon, polyurethane, poly(sulphone),poly(aryletherketone), poly(ethyleneoxide),poly(ethyleneoxide-co-propyleneoxide), poly(vinylpyrrolidine),poly(vinylalcohol), or combinations thereof.

In some embodiments of the present invention, a composition for thetreatment of wounds includes polymeric fibers made from resorbableand/or non-resorbable polymer, where the non-resorbable polymer isselected from proteins, peptides, silk, collagen, polysaccharides,resorbable polyesters, including resorbable polyesters made from hydroxyacids, resorbable polyesters made from diols and diacids;polycarbonates; tyrosine polycarbonates, natural and syntheticpolyamides, natural and synthetic polypeptides, natural and syntheticpolyaminoacids, polyesteramides, poly(alkylene alkylates), polyethers,polyvinyl pyrrolidones, polyurethanes, polyetheresters, polyacetals,polycyanoacrylates, poly(oxyethylene)/poly(oxypropylene) copolymers,polyacetals, polyketals, polyphosphates, (phosphorous-containing)polymers, polyphosphoesters, polyalkylene oxalates, polyalkylenesuccinates, poly(maleic acids), biocompatible copolymers, hydrophilic orwater soluble polymers, or combinations thereof.

In some embodiments of the present invention, a composition for thetreatment of wounds includes polymeric fibers made from collagen, wherethe collagen is selected from Types I, II, III, IV, V or combinationsthereof.

In some embodiments of the present invention, a composition for thetreatment of wounds includes polymeric fibers made from proteins orpeptides, wherein the proteins or peptides include one or more ofalanine, arginine, asparagine, aspartic acid, cysteine, glutamine,glutamic acid, glycine, histidine, isoleucine, lysine, methionine,phenylalanine, proline, serine, threonine, tryptophan, tyrosine andvaline;

In some embodiments of the present invention, a composition for thetreatment of wounds includes polymeric fibers made from polysaccharides,where the polysacchardies are selected from alginate, amylose,carboxymethylcellulose, cellulose, chitin, chitosan, cyclodextrin,dextran, dextrin, gelatin, gellan, glucan, hemicellulose, hyaluronicacid, derivatized hyaluronic acid, oxidized cellulose, pectin, pullulan,sepharose, xanthan and xylan;

In some embodiments of the present invention, a composition for thetreatment of wounds includes resorbable polyesters selected frompoly(lactides), poly(glycolides), poly(lactide-co-glycolides),poly(lactic acid), poly(glycolic acid), poly(lactic acid-co-glycolicacid), poly(dioxanones), polycaprolactones and polyesters with one ormore of the following monomeric units: glycolic, lactic; trimethylenecarbonate, p-dioxanone, -caprolactone, and combinations thereof, and/orthe polyethers are selected from polyethylene glycol (PEG) orpolyethylene oxide (PEO), and/or the biocompatible copolymers areselected from polyethylene (PEG) or (PVP) with a block of a differentbiocompatible or biodegradable polymers selected from poly(lactide),poly(lactide-co-glycolide), polycaprolactone and combinations thereof.

In some embodiments of the present invention, a composition for thetreatment of wounds includes a film layer on the surface of thecomposition that does not contact the wound. In some embodiments, thefilm layer is a laminate film layer that is laminated to the DBF and/orpolymeric fibers. In some embodiments, the film layer is made ofpolyurethane, ethylene vinyl alcohol, or silicone.

In some embodiments of the present invention, a composition for thetreatment of wounds includes a bioactive agent selected from butyricacid, growth factors, inhibitors of matrix metalloproteinases (MMPs),retinols, antioxidants, antibiotics, biofilm inhibitors, vitamins,anti-inflammatory drugs, lipids, steroids, hormones, antibodies,proteins, peptides, glycoproteins, signaling ligands, platelet richplasma, amniotic membrane materials, anti-septic agents, analgesics,anesthetics, immunomodulatory agents, and molecules that promote theformation of extra cellular matrix (ECM), vascularization, and woundhealing.

In some embodiments of the present invention, a composition for thetreatment of wounds includes an antibiotic selected from bacitracin,neomycin, polymixin B, zinc, fusidic acid, gentamicin, mafenide acetate,metronidazole, minocycline, mupirocin, nitrofurazone, polymixin,retapamulin, rifampin, silver particles, silver sulfadiazine,sulfacetamide, vancomycin, and combinations thereof.

In some embodiments of the present invention, a composition for thetreatment of wounds includes DBF that has been treated to remove bonemorphogenic proteins (BMPs) and/or antigenic proteins. In someembodiments, the DBF is treated with a chaotropic agent. In someembodiments, the DBF is treated with a protease.

In some embodiments of the present invention, a method of producing acomposition for treating wounds includes preparing a sheet ofdemineralized bone fibers from cortical bone and/or polymeric fibers. Insome embodiments, the method also includes coating the sheet with anoxygen carrier and/or an oxygen generating material.

In some embodiments of the present invention, the method of producing acomposition for treating wounds includes preparing a sheet ofdemineralized bone fibers from cortical bone and/or polymeric fibers andcoating the sheet with an oxygen carrier and/or an oxygen generatingmaterial selected from Calcium Peroxide, Magnesium Peroxide, SodiumPercarbonate, Sodium Peroxide, or mixtures thereof.

In some embodiments of the present invention, the method of producing acomposition for treating wounds includes preparing a sheet ofdemineralized bone fibers from cortical bone and/or polymeric fibers andcoating the sheet with an oxygen carrier selected from perfluorodecalin,perfluorohexane, perfluoroperhydrophenanthrene, perfluorobutylamine(PFTBA or PFTBM), perfluorooctylbromide (PFOB), perfluoro-n-octane,octafluoropropane, perfluorodichlorooctane, perfluorodecalin (PFD),perfluorotripropylamine, perfluorotrimethylcyclohexane,perfluoromethyladamantane, perfluorodimethyladamantane,perfluoromethyldecaline, perfluorofluorene, diphenyldimethylsiloxane,hydrogen-rich monohydroperfluorooctane, alumina-treated perfluorooctane,or mixtures thereof.

In some embodiments of the present invention, the oxygen generatingmaterial and/or the perfluorocarbon is dispersed in a dispersing agentforming a cream, emulsion, or gel that is coated on the sheet. In someembodiments of the present invention, the dispersing agent is selectedfrom glycerols, phospholipids, lecithins, surfactants, polyoxymers, orcombinations thereof.

In some embodiments of the present invention, the method of producing acomposition for treating wounds includes preparing a sheet ofdemineralized bone fibers from cortical bone and/or polymeric fibers,coating the sheet with an oxygen carrier and/or an oxygen generatingmaterial, and adhering a film layer to a surface of the sheet. In someembodiments of the present invention, the film layer is made ofpolyurethane, ethylene vinyl alcohol, or silicone.

In some embodiments of the present invention, a method of treating awound in a subject having a wound, includes administering thecomposition as disclosed in any embodiment of the present invention. Insome embodiments, the method also includes administering a cream,emulsion, or gel comprising an oxygen generator or a perfluorocarbon tothe composition before or after the administering of the composition tothe subject. In some embodiments, the administering of the cream,emulsion, or gel includes reapplication of the cream, emulsion, or gelon a daily, every other day, every third day, twice a week, or weeklybasis.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a “ball” of demineralized bone fibers (DBF) according toembodiments of the present invention that can be used as a “free form”dressing to pack an irregular shaped wound; in which the fibers areoptionally coated with an oxygen carrier material.

FIG. 2 shows a 4 mm thick sheet of DBF fibers according to embodimentsof the present invention that may be optionally cut by the surgeon tothe size of a wound and placed into it, in which the fibers areoptionally coated/impregnated with an oxygen carrier material.

FIG. 3 shows a 4 mm thick sheet of DBF fibers with a film (e.g.,polyurethane, ethylene vinyl alcohol, or silicone film) laminated to theupper surface to provide moisture control, according to embodiments ofthe present invention.

FIG. 4 shows an “island dressing” wherein a DBF sheet is covered by anadhesive coated film in which the DBF fibers are optionally coated withan oxygen carrier material, according to embodiments of the presentinvention.

DETAILED DESCRIPTION

Embodiments of the present invention include devices and methods forsupporting the formation of new tissue at a wound site of a subject byusing technologies that increase the local oxygen concentration and mayoffset the effects of a lack of vascularity and the utility of usingbone-derived fibers as a scaffold for tissue regeneration.

In some embodiments of the present invention, the oxygen carrier is aperfluorocarbon (PFC). These materials have a very high inherentsolubility for oxygen. Non-limiting examples of PFCs includeperfluorodecalin, perfluorohexane, perfluoroperhydrophenanthrene,perfluorobutylamine (PFTBA or PFTBM), perfluorooctylbromide (PFOB),perfluoro-n-octane, octafluoropropane, perfluorodichlorooctane,perfluorodecalin (PFD), perfluorotripropylamine,perfluorotrimethylcyclohexane, perfluoromethyladamantane,perfluorodimethyladamantane, perfluoromethyldecaline, perfluorofluorene,diphenyldimethylsiloxane, hydrogen-rich monohydroperfluorooctane,alumina-treated perfluorooctane, mixtures thereof, or any suitableoxygen carrier.

Perfluorocarbons are extremely hydrophobic materials and as such thisproperty makes their incorporation into wound dressing materials verydifficult. Embodiments of the present invention include means and/ormethods by which perfluorocarbons are incorporated into wound dressingmaterials.

Some embodiments of the present invention include materials and methodsthrough which oxygen may be generated in the applied dressing. Forexample, calcium peroxide reacts with water to liberate oxygen. Byencapsulation of oxygen-producing or oxygen-enriching materials in aresorbable polymer matrix the rate of evolution of oxygen may becontrolled.

In other embodiments of the present invention, an extracellular matrix(ECM), may be derived from demineralized bone that has utility in woundhealing. In some embodiments, the ECM is made from collagen alone orcollagen is the most abundant component. This ECM provides a matrix thatsupports proliferation and migration of cells, and may be used on itsown, or may incorporate oxygenated or oxygen-generating materials,resulting in a template for accelerated tissue healing.

It has been shown that demineralized bone matrix (DBM) placed into asoft tissue site will stimulate bone formation. Indeed theosteoinductivity of DBM is measured by placing DBM in an intermuscularpouch in athymic rats and evaluating bone formation as disclosed inEdwards, Diegmann, and Scarborough; Clin Orthop Rel Res 357, 219-28,1998, the entire content of which is incorporate by reference.Accordingly, it was surprising to observe that fibers made fromdemineralized bone matrix according to embodiments of the presentinvention were effective at stimulating soft tissue (i.e., non-bone)healing. As described below, there was some transient bone formationobserved, however, surprisingly, good soft tissue healing was stimulatedby the dressing. These isolated, small islands of apparent boneformation activity also appeared to be resorbing. Without being bound byany theory, it is possible that the absence of mechanical loading on thenew bone provides signaling to the bone-like cells to resorb, asdescribed by Wolf's Law, which states that bone in a healthy person oranimal will adapt to the loads under which it is placed.

Bone morphogenic proteins (BMPs) have been identified as important inthe signaling of dermal papilla cells to induce hair follicle inductionas disclosed in Rendl et al. (Rendl, M., Polak, L. and Fuchs, E., 2008.BMP signaling in dermal papilla cells is required for their hairfollicle-inductive properties, Genes & Development, 22(4), pp. 543-557the entire content of which is herein incorporated by reference).Accordingly, there may be particular utility in the use of dressingsaccording to embodiments of the present invention for use in woundswhere subsequent hair production is required or desired.

Methods according to embodiments of the present invention allow for thecontrolled release of oxygen for the treatment of chronic and acutewounds. The devices according to embodiments of the present inventioninclude dressings that temporarily cover a wound (and may be in contactwith a wound) and are subsequently removed from the wound, implants thatare applied to the wound and are not removed, or gels or creams. In allcases, the devices or means (e.g., dressings, implants, gels, or creams)are configured to continually dose the wound with oxygen to promotehealing of the wound. When the device is an implant, it may be aresorbable implant that provides a temporary scaffold to promoteregeneration of the ECM. The scaffolds allow and/or encourage in-growthof cells, tissues, and blood vessels to help regenerate the ECM, inaddition to delivering oxygen to the chronic wound to stimulate andpromote healing.

In the case of a wound resulting from an incision (i.e., an incisionalwound), the oxygenated material in the form of a gel or emulsion may beapplied to the incisional wound tissues prior to closure. A furtheroxygenated dressing may optionally be applied to the skin over theincision.

The resorbable implants may be made from resorbable synthetic or naturalpolymeric materials. In some embodiments of the present invention, thescaffolds of the resorbable implants are made from proteins, such assilk or collagen. In some embodiments, the fibers may be made fromdemineralized and/or devitalized bone. The bone may be allogeneic orxenogeneic.

Oxygen is delivered from the dressing by use of an oxygen carrier, amaterial that inherently has a high oxygen solubility. These materialsmay be directly coated or impregnated into the fibrous dressing materialor may be incorporated into a gel or emulsion. In some embodiments, anoxygen carrier is directly coated on a dressing for utilization inresorbable dressings as it provides the means of incorporating thehighest concentration of oxygen into the dressing.

In some embodiments, the oxygen carrier is a perfluorocarbon (PFC).Non-limiting examples of PFCs include perfluorodecalin, perfluorohexane,perfluoroperhydrophenanthrene, perfluorobutylamine (PFTBA or PFTBM),perfluorooctylbromide (PFOB), perfluoro-n-octane, octafluoropropane,perfluorodichlorooctane, perfluorodecalin (PFD),perfluorotripropylamine, perfluorotrimethylcyclohexane,perfluoromethyladamantane, perfluorodimethyladamantane,perfluoromethyldecaline, perfluorofluorene, diphenyldimethylsiloxane,hydrogen-rich monohydroperfluorooctane, alumina-treated perfluorooctane,mixtures thereof, or any suitable oxygen carrier.

Under ambient conditions when exposed to air, the PFC's will contain thesame ratio of gases found in air.

Saturated or supersaturated forms of the perfluorocarbon may be made byexposing the PFC to a gas at pressure above ambient under temperatureand time conditions necessary to displace other gases in the PFC withthe desired gas. For example, the PFC may be saturated or supersaturatedby exposing the PFC to oxygen. In some embodiments, the oxygen may be inthe form of molecular oxygen, at pressures at or above ambient and undertemperature and time conditions necessary to displace the other gases.The supersaturation of the PFC may be undertaken at the time ofmanufacture in which case the dressing will be packaged in an oxygenbarrier package. Alternatively, the PFC may be added to the dressing atthe time of application and the PFC may be supersaturated at the time ofapplication to the patient.

Perfluorocarbon materials may be formed into emulsions by, for example,vortexing a dispersing agent solution with a PFC. The emulsions may bethickened by the addition of a water soluble polymer into the waterphase of the emulsion. Alternatively, the emulsion may be concentratedby use of a centrifuge.

Non-limiting examples of dispersing agents include glycerols,phospholipids, lecithins, surfactants, polyoxamers, and mixturesthereof.

As would be apparent to one of ordinary skill in the art, when exposedto air under ambient conditions, the PFC's in the emulsion will containthe same ratio of gases found in air.

Saturated or supersaturated forms of the emulsions may be made byexposing the emulsion to a gas at or above ambient pressure undertemperature and time conditions necessary to displace other gases in thePFC with the desired gas. For example, the PFC in the emulsion may besaturated or supersaturated by exposing the emulsion to oxygen, and theoxygen may be in the form of molecular oxygen, with pressures at orabove ambient and under temperature and time conditions necessary todisplace the other gases, or by simply bubbling oxygen through theemulsion.

When the device is a dressing, the dressing may be made from anon-resorbable material or a resorbable material. The oxygen carrier, asdescribed above, may be incorporated directly into the dressing or maybe a cream or gel that is applied regularly to the wound that has beentreated with a dressing according to embodiments of the invention. Wherethe oxygen carrier has been treated to raise the proportion of oxygenthen the dressing must be packaged in materials that prevent diffusionof the oxygen from the product during storage.

The implants according to embodiments of the present invention' providea temporary scaffold for the in-growth of cells, tissues, and bloodvessels to help regenerate the ECM. The delivery of oxygen helps tomaintain cell health and thus facilitates and expedites the healingprocess. Some of the devices according to embodiments of the presentinvention include antibiotics to treat or prevent infection, and/orprotease inhibitors to modulate protease activity in the wound. In apreferred embodiment, the device is an implant including a temporaryresorbable fibrous protein scaffold, such as bone derived extra cellularmatrix, that encourages the in-growth of cells, tissues, and bloodvessels to assist in regenerating the ECM, and promoting healing byreleasing oxygen into the chronic wound.

Oxygen carrier gels may be applied directly to a wound or may be appliedto a wound contacting layer, for example, a silicone gauze (e.g.,Mepitel™).

Oxygen carrier gels or emulsions may also be applied to the deepincision layers of a surgical incision prior to wound closure.

Heterotopic ossification is a problem encountered in combat relatedwounds where tourniquet usage has led to oxygen starvation of tissue.See for example Isaacson et al. 2014 (Isaacson et al. “Tourniquet use incombat-injured service members: a link with heterotopic ossification?”Orthopedic Research and Reviews 6 (2014): 27-31, the entire contents ofwhich are incorporated herein by reference). Tourniquet use duringOperation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF) hascontributed to the high survival rate of combat-injured service members.While preservation of a life even at the potential expense of a limbshould always take precedence, delayed perfusion in traumatized residuallimbs may alter the proliferation, differentiation, and function ofendothelial and osteoprogenitor cells. Given the synergisticrelationship between angiogenesis and osteogenesis, and the influence ofenvironmental conditions on bone formation, hypoxic conditions fromtourniquets may in part explain the higher frequency of heterotopicossification (HO) present during OIF/OEF. Accordingly, the oxygen richdressings as disclosed in embodiments of this invention may haveparticular utility in the treatment of these patients as a battlefielddressing to be applied below the tourniquet.

Definitions

“Healing” as used herein generally refers to the formation of tissue ata site of a wound.

“Subject” is used herein to refer to a human or animal capable of havingor acquiring chronic or acute wounds.

“Bioactive agent” is used herein to refer to therapeutic, prophylactic,and/or diagnostic agents. It includes without limitation physiologicallyor pharmacologically active substances that act locally or systemicallyin the body. “Bioactive agent” includes a single such agent and is alsointended to include a plurality.

“Biocompatible” as generally used herein means the biological responseto the material or device being appropriate for the device's intendedapplication in vivo. Any metabolites of these materials should also bebiocompatible.

“Blend” as generally used herein means a physical combination ofdifferent polymers, as opposed to a copolymer made of two or moredifferent monomers.

“Chronic wounds” is used herein to refer to wounds that have not healedin three months. Chronic wounds also refers to wounds caused by achronic disease or condition in a subject.

“Acute wounds” is used herein to refer to wounds caused by a temporaryincident or condition such as a burn from a fire that may not heal welldue to the age, smoking habits, and/or health of the subject.

“Controlled release” as generally used herein refers to time-dependentrelease of bioactive agents including oxygen. It generally refers to thesustained release of bioactive agents to prolong the therapeutic actionof the bioactive agent, and also to maintain the concentration of thebioactive agent in a therapeutic window.

“Extracellular matrix” or “ECM” as used herein describes a biologicalmaterial derived matrix or scaffold that provides a habitat for cellularpopulation.

“Resorbable” as used herein describes a material that is capable ofbeing broken down in the body and eventually eliminated from the body.The terms “resorbable”, “degradable”, “erodible”, and “absorbable” areused interchangeably in the literature in the field, with or without theprefix “bio”. Herein, these terms will be used interchangeably todescribe material broken down and absorbed or eliminated by the bodywithin five years, whether degradation is due mainly to hydrolysis ormediated by metabolic processes.

Compositions

Materials have been developed to produce devices that allow the releaseof oxygen for the treatment of chronic wounds. Suitable devices includedressings, implants and gels or emulsions. The devices may be used forthe treatment of wounds, including chronic wounds such as venous stasisulcers, diabetic ulcers, pressure ulcers, burns, and surgical wounds.

In one embodiment, dressings may be applied to the chronic wounds, andrelease oxygen into the wound to stimulate healing. These dressings maysubsequently be removed, and if necessary replaced with new dressings.

In another embodiment, the devices may be implants that deliver oxygeninto the wound to stimulate healing. These implants are notsubstantially removed from the wound (although the implants may includeprotective barriers, for example, to control moisture or oxygen in thewound, that may be removed from the surface of the implant). In someembodiments, the implants are temporary scaffolds that are incorporatedinto the body, and allow cell, tissue, and blood vessel in-growth asthey resorb and remodel to appropriate tissue types.

In a further aspect of the invention materials have been developed thathave particular utility as scaffolds for tissue regeneration.

Scaffold Materials

The devices described herein may be produced from polymericcompositions, and/or may be produced from bone-derived collagen, whichmay also be described as bone-derived extra cellular matrix materials.When the devices are dressings, the devices may be made from permanent(i.e. non-resorbable) or resorbable polymeric compositions. When thedevices are implants, the devices may be made from resorbable polymericcompositions, and/or may be made from the bone-derived collagenmaterials.

Extra Cellular Matrix Derived Scaffolds

Biological materials may be used to prepare the implants and dressings.Examples of biological materials include allogenic or xenogenic tissuessuch as acellular dermal matrix materials, cell-seeded dermal matrixmaterial or cell-seeded resorbable polymers, and small intestinesubmucosa. In some embodiments of the present invention, bovine or humanbone is demineralized and fibers formed therefrom following themethodology disclosed in US Patent Publication 2014/0314822 the entirecontent of which is incorporated herein by reference. Fibers mayoptionally be treated with a chaotropic agent such as guanidinehydrochloride to remove bone morphogenic proteins and other materialsnaturally occurring within the demineralized bone fiber material. Fibersfrom a xenogenic source may also be treated with .alpha.-galactosidaseor similar materials to reduce possible immunological response. Fibersmay also be treated with a plasticiser such as glycerol that renders thedried fiber flexible. The fibers may then be formed into a dressingusing wet lay techniques as described in the patent. Alternatively, theentangled fibers (that have not been pre-formed into shapes) may be usedas a fibrous filler to fill the wound on their own. This latter form isparticularly useful for the treatment of irregular or deep wounds suchas pressure sores or decubitus ulcers.

Polymers Non-Resorbable Polymers

Permanent polymers that may be used to prepare the dressings include,but are not limited to, poly(ethylene), poly(propylene),poly(tetrafluoroethylene), poly(methacrylates),poly(methylmethacrylate), poly(ethylene-co-vinylacetate),poly(dimethylsiloxane), poly(ether-urethanes), poly(ethyleneterephthalate), nylon, polyurethane, poly(sulphone), andpoly(aryletherketone).

Resorbable Polymers

Resorbable polymers that may be used to prepare the devices (dressingsor implants) include, but are not limited to, proteins, including silk,collagen (including Types I to V and mixtures thereof), collagen-basedextra cellular matrix, and proteins including one or more of thefollowing amino acids: alanine, arginine, asparagine, aspartic acid,cysteine, glutamine, glutamic acid, glycine, histidine, isoleucine,lysine, methionine, phenylalanine, proline, serine, threonine,tryptophan, tyrosine and valine; polysaccharides, including alginate,amylose, carboxymethylcellulose, cellulose, chitin, chitosan,cyclodextrin, dextran, dextrin, gelatin, gellan, glucan, hemicellulose,hyaluronic acid, derivatized hyaluronic acid, oxidized cellulose,pectin, pullulan, sepharose, xanthan and xylan; resorbable polyesters,including resorbable polyesters made from hydroxy acids (includingresorbable polyesters like poly(lactides), poly(glycolides),poly(lactide-co-glycolides), poly(lactic acid), poly(glycolic acid),poly(lactic acid-co-glycolic acid), poly(dioxanones), polycaprolactonesand polyesters with one or more of the following monomeric units:glycolic, lactic; trimethylene carbonate, p-dioxanone, or.quadrature.-caprolactone), and resorbable polyesters made from diolsand diacids; polycarbonates; tyrosine polycarbonates; polyamides(including synthetic and natural polyamides, polypeptides, andpoly(amino acids)); polyesteramides; poly(alkylene alkylates);polyethers (such as polyethylene glycol, PEG, and polyethylene oxide,PEO); polyvinyl pyrrolidones or PVP; polyurethanes; polyetheresters;polyacetals; polycyanoacrylates; poly(oxyethylene)/poly(oxypropylene)copolymers; polyacetals, polyketals; polyphosphates;(phosphorous-containing) polymers; polyphosphoesters; polyalkyleneoxalates; polyalkylene succinates; poly(maleic acids); biocompatiblecopolymers (including block copolymers or random copolymers); andhydrophilic or water soluble polymers, such as polyethylene glycol,(PEG) or polyvinyl pyrrolidone (PVP), with blocks of other biocompatibleor biodegradable polymers, for example, poly(lactide),poly(lactide-co-glycolide), or polycaprolactone or combinations thereof.Resorbable polymers also include cross-linked polymers, and include, forexample, cross-linked collagen, as well as functionalized polymers.Particularly preferred resorbable polymers are resorbable polyesters.

If desired, the scaffold materials described herein may be formed from amixture of the extracellular matrix derived and polymer fibers toproduce the dressings and implants.

It should be noted that although the implants may be made fromresorbable polymeric compositions, the implants may under circumstancesincorporate permanent materials that do not remain in or on the body.For example, a device including a resorbable implant may alsoincorporate a permanent material, such as film, to control the moisturecontent of the wound, act as an oxygen barrier, and/or preventinfection, as depicted in FIG. 3. Although a resorbable implant is leftin the wound to resorb and remodel, the permanent material is eventuallyremoved.

Bioactive Agents

In addition to incorporating an oxygen carrier into the devices tostimulate healing, other bioactive agents may also be incorporated.These bioactive agents may be added during the preparation of thepolymeric compositions, or may be added later to the devices. They maybe added before, during or at the same time as the oxygen carrier. Thebioactive agents may be added by using aqueous or solvent-basedprocesses or melt-based processes.

Examples of bioactive agents that can be incorporated into the devicesinclude, but are not limited to, angiogenic factors such as butyricacid, growth factors (e.g. VEG-F), inhibitors of matrixmetalloproteinases (MMPs), agents such as retinols to aid oxygendiffusion through the tissue, antioxidants such as ascorbates toameliorate the effects of reactive oxygen species, antibiotics(including silver particles), biofilm inhibitors, vitamins,anti-inflammatory drugs, lipids, steroids, hormones, antibodies,proteins, peptides, glycoproteins, signaling ligands, platelet richplasma, amniotic membrane materials, anti-septic agents, analgesics,anesthetics, immunomodulatory agents, molecules that promote theformation of ECM, vascularization, and wound healing. Particularlypreferred antibiotics include bacitracin, neomycin, polymixin B, zinc,fusidic acid, gentamicin, mafenide acetate, metronidazole, minocycline,mupirocin, nitrofurazone, polymixin, retapamulin, rifampin, silverparticles, silver sulfadiazine, sulfacetamide, vancomycin, andcombinations thereof.

Oxygenating Agents

High Oxygen Solubility Materials. Materials such as perfluorocarbonshave a high inherent oxygen solubility and can act as a reservoir ofoxygen within an implant.

Non-limiting examples of PFCs include perfluorodecalin, perfluorohexane,perfluoroperhydrophenanthrene, perfluorobutylamine (PFTBA or PFTBM),perfluorooctylbromide (PFOB), perfluoro-n-octane, octafluoropropane,perfluorodichlorooctane, perfluorodecalin (PFD),perfluorotripropylamine, perfluorotrimethylcyclohexane,perfluoromethyladamantane, perfluorodimethyladamantane,perfluoromethyldecaline, perfluorofluorene, diphenyldimethylsiloxane,hydrogen-rich monohydroperfluorooctane, alumina-treated perfluorooctane,mixtures thereof, or any suitable oxygen carrier.

In a further design of the device, the perfluorocarbon is incorporatedinto an emulsion or gel prior to coating the fibers of the dressing.

In a further design of the device, the perfluorocarbon-coated fibersinclude one layer of a multi-layer laminate dressing.

Perfluorocarbon materials may be formed into emulsions by, for example,vortexing a dispersing agent solution with a PFC. The emulsions may bethickened by the addition of a water soluble polymer into the waterphase of the emulsion. Alternatively, the emulsion can be concentratedby use of a centrifuge.

Non-limiting examples of dispersing agents include glycerols,phospholipids, lecithins, surfactants, and polyoxamers.

Oxygen-Generating Materials. Oxygen is generated by the breakdown ofmaterials such as Calcium Peroxide, Magnesium Peroxide, SodiumPercarbonate, or Sodium Peroxide. In some instances Hydrogen Peroxidemay be an intermediate product that requires catalysis for it to breakdown. Catalysts such as catalase or zinc oxide can be used.

As used herein, an oxygen-generating material is also referred to as an“oxygen generator.” Ideally the oxygen generating material isencapsulated in a resorbable polymer to affect control over the rate ofwater exposure to the oxygen generator and hence control the rate ofoxygen generation.

Resorbable polymers that may be used to encapsulate the oxygen generatorinclude, but are not limited to, proteins, including silk, collagen(including Types I to V and mixtures thereof), and proteins includingone or more of the following amino acids: alanine, arginine, asparagine,aspartic acid, cysteine, glutamine, glutamic acid, glycine, histidine,isoleucine, lysine, methionine, phenylalanine, proline, serine,threonine, tryptophan, tyrosine and valine; polysaccharides, includingalginate, amylose, carboxymethylcellulose, cellulose, chitin, chitosan,cyclodextrin, dextran, dextrin, gelatin, gellan, glucan, hemicellulose,hyaluronic acid, derivatized hyaluronic acid, oxidized cellulose,pectin, pullulan, sepharose, xanthan and xylan; resorbable polyesters,including resorbable polyesters made from hydroxy acids (includingresorbable polyesters like poly(lactides), poly(glycolides),poly(lactide-co-glycolides), poly(lactic acid), poly(glycolic acid),poly(lactic acid-co-glycolic acid), poly(dioxanones), polycaprolactonesand polyesters with one or more of the following monomeric units:glycolic, lactic; trimethylene carbonate, p-dioxanone, or.quadrature.-caprolactone), and resorbable polyesters made from diolsand diacids; polycarbonates; tyrosine polycarbonates; polyamides(including synthetic and natural polyamides, polypeptides, andpoly(amino acids)); polyesteramides; poly(alkylene alkylates);polyethers (such as polyethylene glycol, PEG, and polyethylene oxide,PEO); polyvinyl pyrrolidones or PVP; polyurethanes; polyetheresters;polyacetals; polycyanoacrylates; poly(oxyethylene)/poly(oxypropylene)copolymers; polyacetals, polyketals; polyphosphates;(phosphorous-containing) polymers; polyphosphoesters; polyalkyleneoxalates; polyalkylene succinates; poly(maleic acids); biocompatiblecopolymers (including block copolymers or random copolymers); andhydrophilic or water soluble polymers, such as polyethylene glycol,(PEG) or polyvinyl pyrrolidone (PVP), with blocks of other biocompatibleor biodegradable polymers, for example, poly(lactide),poly(lactide-co-glycolide), or polycaprolactone or combinations thereof.Resorbable polymers also include cross-linked polymers, and include, forexample, cross-linked collagen, as well as functionalized polymers. Insome embodiments of the present invention, resorbable polymers includeresorbable polyesters.

Use of a core-sheath fiber system with high load of the oxygen generatorin the core allows ability to protect the system to give storagestability and to control the rate of oxygen generation. It also allowsthe physical properties of the fiber to be dictated by the sheath.

A porogen such as calcium carbonate may also be included in the outersheath to also provide buffering capacity to help maintain a physiologicpH in instances where the breakdown of the oxygen generator leads to alowering of the pH. Alternatively, buffering agents and catalysts may beformulated into the oxygen generating core material.

Wound Healing Devices and Methods of Manufacturing

Methods have been developed to produce dressings that can be used totreat wounds derived from allogenic or xenogenic bone and devices thatallow the release of oxygen for the treatment of chronic wounds.

Wound Healing Devices Manufactured from Bone Derived Fibers

Fibers may be manufactured from demineralized bone using, for example,the methods disclosed in US Patent Publication 2014/0314822, the entirecontent of which is incorporated herein by reference. The bone is cutinto struts that are then placed in dilute acid to effectdemineralization. The demineralized struts are then cut using a blade toform ribbon like fibers that may be up to 4 cm in length or greater and0.1 to 1.5 mm wide and 0.05 to 0.5 mm thick. The bone may be derivedfrom human, bovine, porcine or other animal sources. The demineralizedbone fibers (DBFs) may be derived from allogeneic or xenogenic corticalbone. For utility in soft tissue healing the demineralized bone fibers(DBFs) may be optionally treated to remove bone morphogenic proteins orother naturally present materials. A number of suitable methods exist.For example, the fibers may be treated with Guanidine Hydrochloride.Fibers from a xenogenic source may also be treated with.alpha.-galactosidase or similar materials to reduce possibleimmunological response. The resultant fibers can then be processed usinga wet lay technique to produce a fiber dressing. Cohesion of thedressing is optionally improved by use of a heat treatment step, asdisclosed in the patent application. The dressing may be optionallydried, or may be packaged and sterilized in its partially hydratedstate.

Optionally the demineralized bone fibers may be dried and thenrehydrated in a glycerol solution prior to the wet lay process and driedby lyophilization afterward. This renders a flexible DBF dressing in theabsence of aqueous hydration.

The DBF dressing has utility as a wound dressing without furthermodification. It may however have a control film laminated to it. Suchfilms could be, for example, a polyurethane film to control moisturetransmission, or a silicone film to control oxygen transfer, such thatit is directed towards the wound, or other materials that mightfacilitate application and handling of the dressing by a nurse orpatient.

Oxygenating Creams and Treatments for Wound Dressings

The demineralized bone fiber dressing may optionally be furthertransformed to deliver oxygen by coating the fibers with a material witha high inherent oxygen solubility, such as a perfluorocarbon.

Non-limiting examples of PFCs include perfluorodecalin, perfluorohexane,perfluoroperhydrophenanthrene, perfluorobutylamine (PFTBA or PFTBM),perfluorooctylbromide (PFOB), perfluoro-n-octane, octafluoropropane,perfluorodichlorooctane, perfluorodecalin (PFD),perfluorotripropylamine, perfluorotrimethylcyclohexane,perfluoromethyladamantane, perfluorodimethyladamantane,perfluoromethyldecaline, perfluorofluorene, diphenyldimethylsiloxane,hydrogen-rich monohydroperfluorooctane, alumina-treated perfluorooctane,mixtures thereof, or any suitable oxygen carrier.

In a further design of device the perfluorocarbon is incorporated intoan emulsion or gel prior to coating the fibers of the dressing. Variouscoating techniques may be used including dip coating, roller coating,blade over flat bed coating or other methods as any person skilled inthe art would know.

Alternatively, the bone fiber dressing may optionally be furthertransformed to deliver oxygen by incorporating an oxygen generatingmaterial.

In some embodiments of the present invention, the oxygen generatingmaterials are fibers that are mixed in with the DBF prior to forming thedressing by a wet lay process. In instances where water sensitivematerials are used the wet lay process may use a non-aqueous solventsuch as alcohol. Alternatively, other conventional textile processessuch as carding, needling and/or point bonding may be used.

Wound Healing Devices Manufactured from Other Fibers

Rather than use bone derived fibers it would also be possible to usecollagen fibers derived from some other source, such as bovine tendoncollagen. Alternatively, fibers from any of the polymers disclosed abovemay be used to form a non-woven material. The fibers may be formed byelectro spinning, melt, wet or solvent spinning. The non-woven materialcan be formed directly or by a subsequent process such as carding andneedling or point bonding.

Non-woven dressings can then be coated with perfluorocarbon orperfluorocarbon gels or emulsions as described above. A film layer mayalso be laminated onto the dressing as described above.

Wound Healing Devices Manufactured from Foams and Sponges

The devices may contain foams, including open or reticulated cell foams,sponges, and other porous forms. These foams may be produced, forexample, by phase-separation, melt-foaming, and particulate leachingmethods. Alternatively, a film is frozen to precipitate the polymer, andthe solvent sublimated using, for example, a lyophilizer, to form aphase separated porous polymeric foam.

The foams may also be produced by particulate leaching methods. Poresize and density may be controlled by selection of the leachablematerial, its size and quantity. Foams may be formed by dispersingparticles in a solution of a permanent or resorbable polymer describedabove, wherein the particles do not dissolve in the solvent. The solventis subsequently evaporated, and the particles leached away with asolvent that dissolves just the particles. The foams may also beproduced by melt-foaming using blowing agents.

The oxygen carrier may be incorporated as part of the foam formingformulation or alternatively the foam can be infused with the oxygencarrier using a coating or impregnation process.

Wound Healing Devices Manufactured from Gels

Perfluorocarbon materials may be formed into emulsions as describedabove. The emulsions may be thickened by the addition of a water solublepolymer into the water phase of the emulsion. Alternatively, theemulsion may be concentrated by use of a centrifuge. The gels may beapplied directly to a wound or may be applied to a wound contactinglayer such as a silicone gauze such as Mepitel™.

Non-limiting examples of dispersing agents include glycerols,phospholipids, lecithins, surfactants, and polyoxymers.

Wound Healing Devices Manufactured from Laminates

Devices according to embodiments of the present invention may containlaminate structures including the materials described above. Ininstances where a dressing is non-resorbable and requires removal fromthe wound, a non-adherent wound facing layer may be utilized. The layerof the dressing incorporating the perfluorocarbon material may have afurther layer laminated to form an outer surface away from the woundthat provides control of moisture vapor or oxygen permeability. Foroxygen permeability, the layer may have low oxygen permeability suchthat egress of oxygen from the dressing is directed towards the wound.

For heavily exuding wounds, a device according to embodiments of thepresent invention include an additional absorbent layer that is capableof being laminated onto the perfluorocarbon containing layer.

In instances where the dressing is resorbable and is designed to beincorporated into the subject (human or animal patient), the dressingmay be perforated to enhance ingrowth and allow excessive exudation toegress the wound. An outer permeability controlling layer may benon-absorbable and be designed to be removed from the patient atdressing changes.

Methods of Using the Wound Healing Devices, and Their Applications

The devices according to embodiments of the present invention may beused as dressings for wound healing or they may be used as implants ifat least part of the device is resorbable. In some embodiments of thepresent invention, the devices are used for the treatment of acute orchronic wounds. In some embodiments of the present invention, thedevices are used for the treatment of chronic wounds, including venousstasis ulcers, diabetic ulcers, pressure ulcers, burns, trauma wounds,and surgical wounds.

The oxygen generating or oxygenated dressings may also be used to wrap alimb below a tourniquet following trauma, such as an explosion from animprovised explosive device (IED). For this indication, the outer partof the dressing may be laminated with an oxygen barrier polymer film tomaintain the generated oxygen in the wound. Alternatively, the oxygenbarrier film may be a separate bandage applied over the oxygengenerating dressings.

Devices according to embodiments of the present invention are placed onor in a wound so that the oxygen may enter the wound. The devices mayincorporate adhesives to help keep the device in place, and/or thedevices may be held in place by another wound dressing material. Forexample, the devices may be held in place using compression dressings,such as when the devices are used to treat venous stasis ulcers. Inanother embodiment the dressing is an island on an adhesive coated filmor fabric as depicted in FIG. 4.

In some embodiments of the present invention, the devices contain poressuitable for in-growth of blood vessels, cells and tissue when thedevices are used as implants. In some embodiments, the devices may beleft in place in the wound if they are resorbable implants, and do notneed to be removed from the wound. However, these implants may alsoincorporate, for example, a moisture barrier or protective barrier thatdoes need to be removed leaving behind the remainder of the implant.

In some embodiments of the present invention, the devices may also beused as dressings and removed after a period of time or replaced after ashort period of time. In some embodiments, the dressing may be replacedor an additional implant ay be placed in the wound in order to maintaina delivery of oxygen to the wound.

The following Examples are presented for illustrative purposes only, anddo not limit the scope or content of the present application.

EXAMPLE 1

Struts of porcine bone weighing 300 grams were placed in 3000 ml 0.6Mhydrochloric acid for 6 days, with the acid changed every day. Afterthis time the struts were demineralized, as could be confirmed by theability to bend them by hand. They were rinsed in buffer and stored in afreezer until the next step in the process. A blade with openings0.030″.times.0.050″ and a tooth height of 0.012″ was used to producefibers (as shown in FIG. 1). The fibers were placed in phosphatebuffered saline for 45 minutes.

Fibers weighing 150 grams were placed in 1500 ml of 4M GuanidineHydrochloride and placed on a shaker table for 16 hours to remove thebone morphogenic proteins and other naturally present materials.

A 3 mm thick sheet of fibers was made. This was made using a wet laytechnique. 45 grams of fibers were suspended in saline to form a slurryand added to a wet lay apparatus having a 4 inch by 4 inch screen. Thesheet of fiber on the wet lay screen was removed and placed into a moldthat pressed the sheet to a thickness of about 3 mm and then was heatedat 50.degree. C. for about an hour with a compression weight placed ontop of the fiber sheet. As produced the fiber sheet is usable as adressing.

EXAMPLE 2

Struts of porcine bone weighing 300 grams were placed in 3000 ml 0.6Mhydrochloric acid for 6 days, with the acid changed every day. Afterthis time the struts were demineralized, as could be confirmed by theability to bend them by hand. They were rinsed in buffer and stored in afreezer until the next step in the process. A blade with openings0.030″.times.0.050″ and a tooth height of 0.012″ was used to producefibers. The fibers were placed in phosphate buffer for 45 minutes.

A 3 mm thick sheet of fibers was made. This was made using a wet laytechnique. 45 grams of fibers were suspended in saline to form a slurryand added to a wet lay apparatus having a 4 inch by 4 inch screen. Thesheet of fiber on the wet lay screen was removed and placed into a moldthat pressed the sheet to a thickness of about 3 mm and then was heatedat 50.degree. C. for about an hour with a compression weight placed ontop of the fiber sheet. As produced the fiber sheet is usable as adressing.

EXAMPLE 3

Struts of rabbit bone weighing 300 grams were placed in 3000 ml 0.6Mhydrochloric acid for 6 days, with the acid changed every day. Afterthis time the struts were demineralized, as could be confirmed by theability to bend them by hand. They were rinsed in buffer and stored in afreezer until the next step in the process. A blade with openings0.030″.times.0.050″ and a tooth height of 0.012″ was used to producefibers. The fibers were placed in phosphate buffer for 45 minutes.

Fibers were blotted to remove excess buffer and 1 gram placed in jarsand foil pouches. Thereafter the product was sterilized using electronbeam sterilization.

The fibers were hydrated and formed an entangled mass, or “putty” thatcould be utilized as a dressing to pack a wound.

EXAMPLE 4

A fiber dressing of Example 1 was dried overnight in a vacuum oven setat 25.degree. C. with a 0.6 L/min air in-flow rate. The dried dressingweighed 13 grams. The dressing was placed in a tray and 8 grams ofperfluorotributylamine (PFTBA, Sigma Aldrich) was applied to thedressing. A roller was used to ensure uniform distribution of the PFTBA.

EXAMPLE 5

A fiber dressing of Example 1 was dried overnight in a vacuum oven setat 25.degree. C. with a 0.6 L/min air in-flow rate. The dried dressingweighed 13 grams. The dressing was placed in a tray and 8 grams ofperfluorodecalin (PFD, Fluoromed) was applied to the dressing. A rollerwas used to ensure uniform distribution of the PFTBA.

EXAMPLE 6

A series of perfluorocarbon emulsions were made. Emulsifier solutionswere made using Polyoxamer F127 (Sigma Aldrich) at concentrations of0.01, 0.05 and 0.1 gram/ml. Emulsions were made using these solutionswith 3 mls of perfluorodecalin and 2 mls of each of the emulsifiersolutions. Mixing was achieved by rapidly passing the solutions betweentwo syringes joined with a Luer connector. All three formulationsproduced emulsions.

EXAMPLE 7

A series of perfluorocarbon emulsions were made. Emulsifier solutionswere made using Polyoxamer F68 (Sigma Aldrich) at concentrations of0.01, 0.05 and 0.1 gram/ml. Emulsions were made using these solutionswith 3 mls of perfluorodecalin and 2 mls of each of the emulsifiersolutions. Mixing was achieved by rapidly passing the solutions betweentwo syringes joined with a Luer connector. All three formulationsproduced emulsions.

EXAMPLE 8

A series of perfluorocarbon emulsions were made. Emulsifier solutionswere made using Polysorbate 20 (Sigma Aldrich) at concentrations of0.01, 0.05 and 0.1 gram/ml. Emulsions were made using these solutionswith 3 mls of perfluorodecalin and 2 mls of each of the emulsifiersolutions. Mixing was achieved by rapidly passing the solutions betweentwo syringes joined with a Luer connector. All three formulationsproduced emulsions.

EXAMPLE 9

An emulsion of Example 6 made using Polyoxamer at 0.1 gram/ml was placedin a centrifuge. After centrifuging the emulsion had formed into aconcentrated gel below a water/polyoxamer solution supernatant. Thesupernatant was removed to yield a concentrated perfluorocarbon gel.

EXAMPLE 10

A fiber dressing of Example 1 was dried overnight in a vacuum oven setat 25.degree. C. with a 0.6 L/min air in-flow rate. The dried dressingweighed 13 grams. The dressing was placed in a tray and 8 grams of thegel of example 9 was applied to the dressing. A roller was used toensure uniform distribution of the gel.

EXAMPLE 11

A series of dressings and perfluorcarbon treatments were evaluated in aporcine full thickness dermal wound model. 2 cm.times.2 cm fullthickness defects, approximately 4 mm deep were produced on the back ofpigs. The following treatments were evaluated, all with a Tegaderm™polyurethane film dressing applied to protect the treatment:

1. Porcine DBF 4 mm thick fiber dressing (as shown in FIG. 2)

2. Porcine DBF (Guanidine Hydrochloride extracted) 4 mm thick fiberdressing

3. Rabbit DBF Fiber “Putty”

Results

Wounds were examined daily and the Tegaderm dressing changed every 3days for a total treatment time of 21 or 28 days. Histological sectionswere taken and processed using Haemotoxylin & Eosin (H&E), and ElastinVierhoff Von Giessen stain. A blind histological review was undertakenby a clinical dermatopathologist.

Porcine DBFs were well integrated into full thickness porcine wounds,and normal granulation, vascularization, and new collagen deposition. Asexpected, re-epithelialization was slightly delayed, as the presence ofthe scaffold diminished wound contracture (the type of healing thatoccurs in porcine wounds, but not as common in human wounds). There wasa significant foreign body response and some osteoid formation withosteoclast like giant cells within the healing porcine skin. Thethickness of the healing dermis was better preserved with less of anindented scar than wounds that did not have scaffold present. There weremore hair follicles in wounds treated with intact DBF than any othergroup, which suggests that signals from the DBF may have regenerativeproperties.

Porcine guanidine-extracted DBF integrated well into porcine wounds andnormal granulation, vascularization, and new collagen depositionappeared normal. Guanidine extracted DBF resulted in less of a foreignbody response than non-guanidine extracted DBF, with no osteoidformation. The thickness of the dermis was better preserved than woundswithout the scaffold, but there was a slight delay inre-epithelialization, as the presence of the scaffold prevented woundcontracture (the normal mechanism of healing of full thickness porcinewounds).

Rabbit DBF resulted in a robust foreign body response along with osteoidformation. Re-epithelialization was delayed and there was moregranulation tissue and immature blood vessel formation, suggesting thatthe greater inflammatory response to the rabbit DBF was inhibiting woundhealing compared to the porcine DBFs.

While the present invention has been illustrated and described withreference to certain exemplary embodiments, those of ordinary skill inthe art will understand that various modifications and changes of thedevices, processes, and methods described herein may be made to thedescribed embodiments without departing from the spirit and scope of thepresent invention, as defined in the following claims.

1. A composition for the treatment of wounds, comprising: demineralizedbone fibers (DBF) derived from allogeneic or xenogenic cortical bone. 2.A composition for the treatment of wounds, comprising: polymeric fibersmade from resorbable and/or non-resorbable polymer.
 3. The compositionof claim 1, further comprising polymeric fibers made from resorbableand/or non-resorbable polymers.
 4. The composition of claim 1, furthercomprising oxygen generating materials and/or an oxygen carrier.
 5. Thecomposition of claim 4, wherein the oxygen generating materials and/orthe oxygen carrier is coated on the DBF or the polymeric fibers.
 6. Thecomposition of claim 4, wherein the oxygen generating materials areselected from the group consisting of Calcium Peroxide, MagnesiumPeroxide, Sodium Percarbonate, Sodium Peroxide, and mixtures thereof. 7.The composition of claim 4, wherein the oxygen carrier is aperfluorocarbon selected from the group consisting of perfluorodecalin,perfluorohexane, perfluoroperhydrophenanthrene, perfluorobutylamine(PFTBA or PFTBM), perfluorooctylbromide (PFOB), perfluoro-n-octane,octafluoropropane, perfluorodichlorooctane, perfluorodecalin (PFD),perfluorotripropylamine, perfluorotrimethylcyclohexane,perfluoromethyladamantane, perfluorodimethyladamantane,perfluoromethyldecaline, perfluorofluorene, diphenyldimethylsiloxane,hydrogen-rich monohydroperfluorooctane, alumina-treated perfluorooctane,and mixtures thereof.
 8. The composition of claim 2, wherein thenon-resorbable polymer is selected from the group consisting ofpoly(ethylene), poly(propylene), poly(tetrafluoroethylene),poly(methacrylates), poly(methylmethacrylate), ethylene-co-vinylacetate,poly(dimethylsiloxane), poly(ether-urethanes), poly(ethyleneterephthalate), nylon, polyurethane, poly(sulphone),poly(aryletherketone), poly(ethyleneoxide),poly(ethyleneoxide-co-propyleneoxide), poly(vinylpyrrolidine),poly(vinylalcohol), and combinations thereof.
 9. The composition ofclaim 2, wherein the resorbable polymer is selected from the groupconsisting of proteins, peptides, silk, collagen, polysaccharides,resorbable polyesters, including resorbable polyesters made from hydroxyacids, resorbable polyesters made from diols and diacids;polycarbonates; tyrosine polycarbonates, natural and syntheticpolyamides, natural and synthetic polypeptides, natural and syntheticpolyaminoacids, polyesteramides, poly(alkylene alkylates), polyethers,polyvinyl pyrrolidones, polyurethanes, polyetheresters, polyacetals,polycyanoacrylates, poly(oxyethylene)/poly(oxypropylene) copolymers,polyacetals, polyketals, polyphosphates, (phosphorous-containing)polymers, polyphosphoesters, polyalkylene oxalates, polyalkylenesuccinates, poly(maleic acids), biocompatible copolymers, hydrophilic orwater soluble polymers, and combinations thereof.
 10. The composition ofclaim 9, wherein: the collagen is selected from the group consisting ofTypes I, II, III, IV, V and combinations thereof; the proteins orpeptides include one or more of alanine, arginine, asparagine, asparticacid, cysteine, glutamine, glutamic acid, glycine, histidine,isoleucine, lysine, methionine, phenylalanine, proline, serine,threonine, tryptophan, tyrosine and valine; the polysaccharides areselected from alginate, amylose, carboxymethylcellulose, cellulose,chitin, chitosan, cyclodextrin, dextran, dextrin, gelatin, gellan,glucan, hemicellulose, hyaluronic acid, derivatized hyaluronic acid,oxidized cellulose, pectin, pullulan, sepharose, xanthan and xylan; theresorbable polyesters are selected from the group consisting ofpoly(lactides), poly(glycolides), poly(lactide-co-glycolides),poly(lactic acid), poly(glycolic acid), poly(lactic acid-co-glycolicacid), poly(dioxanones), polycaprolactones and polyesters with one ormore of the following monomeric units: glycolic, lactic; trimethylenecarbonate, p-dioxanone, or .epsilon.-caprolactone; the polyethers areselected from polyethylene glycol (PEG) or polyethylene oxide (PEO); andthe biocompatible copolymers are selected from the group consisting ofpolyethylene (PEG) or (PVP) with a block of a different biocompatible orbiodegradable polymers selected from the group consisting ofpoly(lactide), poly(lactide-co-glycolide), polycaprolactone, andcombinations thereof.
 11. The composition of claim 4, further comprisinga film layer on the surface of the composition that does not contact thewound.
 12. The composition of claim 11, wherein the film layer is alaminate film layer that is laminated to the DBF and/or polymericfibers.
 13. The composition of claim 11, wherein the film layer is madeof polyurethane, ethylene vinyl alcohol, or silicone.
 14. Thecomposition of claim 4, further comprising a bioactive agent selectedfrom the group consisting of butyric acid, growth factors, inhibitors ofmatrix metalloproteinases (MMPs), retinols, antioxidants, antibiotics,biofilm inhibitors, vitamins, anti-inflammatory drugs, lipids, steroids,hormones, antibodies, proteins, peptides, glycoproteins, signalingligands, platelet rich plasma, amniotic membrane materials, anti-septicagents, analgesics, anesthetics, immunomodulatory agents, and moleculesthat promote the formation of extra cellular matrix (ECM),vascularization, and wound healing.
 15. The composition of claim 1,wherein the DBF is treated to remove bone morphogenic proteins (BMPs)and/or antigenic proteins.
 16. The composition of claim 15, wherein theDBF is treated with a chaotropic agent.
 17. The composition of claim 16,wherein the DBF is treated with a protease.
 18. A method of producing acomposition for treating wounds, the method comprising: preparing asheet of demineralized bone fibers from cortical bone and/or polymericfibers.
 19. The method of claim 18, further comprising: coating thesheet with an oxygen carrier and/or an oxygen generating material. 20.The method of claim 19, wherein the oxygen generating materials areselected from the group consisting of Calcium Peroxide, MagnesiumPeroxide, Sodium Percarbonate, Sodium Peroxide, and mixtures thereof.21. The method of claim 19 wherein the oxygen generating materialscomprise calcium peroxide.